unlambda (empty) → 0.1
raw patch · 5 files changed
+558/−0 lines, 5 filesdep +arraydep +basedep +mtlsetup-changed
Dependencies added: array, base, mtl, unix
Files
- LICENSE +340/−0
- Language/Unlambda.hs +144/−0
- Main.hs +39/−0
- Setup.hs +5/−0
- unlambda.cabal +30/−0
+ LICENSE view
@@ -0,0 +1,340 @@+ GNU GENERAL PUBLIC LICENSE+ Version 2, June 1991++ Copyright (C) 1989, 1991 Free Software Foundation, Inc.+ 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA+ Everyone is permitted to copy and distribute verbatim copies+ of this license document, but changing it is not allowed.++ Preamble++ The licenses for most software are designed to take away your+freedom to share and change it. By contrast, the GNU General Public+License is intended to guarantee your freedom to share and change free+software--to make sure the software is free for all its users. This+General Public License applies to most of the Free Software+Foundation's software and to any other program whose authors commit to+using it. (Some other Free Software Foundation software is covered by+the GNU Library General Public License instead.) You can apply it to+your programs, too.++ When we speak of free software, we are referring to freedom, not+price. 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+ Language/Unlambda.hs view
@@ -0,0 +1,144 @@+{-# OPTIONS -fglasgow-exts #-}++{-+Uses pattern guards++This is an interpreter of the Unlambda language, written in+the pure, lazy, functional language Haskell.++Copyright (C) 2001 by Ørjan Johansen <oerjan@nvg.ntnu.no>+Copyright (C) 2006 by Don Stewart - http://www.cse.unsw.edu.au/~dons++This program is free software; you can redistribute it and/or modify+it under the terms of the GNU General Public License as published by+the Free Software Foundation; either version 2 of the License, or+(at your option) any later version.++This program is distributed in the hope that it will be useful,+but WITHOUT ANY WARRANTY; without even the implied warranty of+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the+GNU General Public License for more details.++You should have received a copy of the GNU General Public License+along with this program; if not, write to the Free Software+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA+-}++module Language.Unlambda where++------------------------------------------------------------------------+-- Abstract syntax++data Exp+ = App Exp Exp+ | K+ | K1 Exp+ | S+ | S1 Exp+ | S2 Exp Exp+ | I+ | V+ | C+ | Cont (Cont Exp)+ | D+ | D1 Exp+ | Dot Char+ | E+ | At+ | Ques Char+ | Pipe++------------------------------------------------------------------------+-- Printing++instance Show Exp where showsPrec _ e = sh e++sh :: Exp -> String -> String+sh (App x y) = showChar '`' . sh x . sh y+sh K = showChar 'k'+sh (K1 x) = showString "`k" . sh x+sh S = showChar 's'+sh (S1 x) = showString "`s" . sh x+sh (S2 x y) = showString "``s" . sh x . sh y+sh I = showChar 'i'+sh V = showChar 'v'+sh C = showChar 'c'+sh (Cont _) = showString "<cont>"+sh D = showChar 'd'+sh (D1 x) = showString "`d" . sh x+sh (Dot '\n') = showChar 'r'+sh (Dot c) = showChar '.' . showChar c+sh E = showChar 'e'+sh At = showChar '@'+sh (Ques c) = showChar '?' . showChar c+sh Pipe = showChar '|'++------------------------------------------------------------------------+-- Eval monad++newtype Eval a = Eval ((Maybe Char, Int) -> Cont a -> IO Exp)++type Cont a = (Maybe Char, Int) -> a -> IO Exp++instance Monad Eval where++ (Eval cp1) >>= f = Eval $ \dat1 cont2 ->+ cp1 dat1 $ \dat2 a ->+ let (Eval cp2) = f a in cp2 dat2 cont2++ return a = Eval $ \dat cont -> cont dat a++------------------------------------------------------------------------+-- Basics++currentChar :: Eval (Maybe Char)+currentChar = Eval (\dat@(c,_) cont -> cont dat c)+setCurrentChar :: Maybe Char -> Eval ()+setCurrentChar c = Eval (\(_,i) cont -> cont (c,i) ())+io :: IO a -> Eval a+io iocp = Eval (\dat cont -> iocp >>= cont dat)+throw :: ((Maybe Char, Int) -> t -> IO Exp) -> t -> Eval a+throw c x = Eval (\dat _ -> c dat x)+exit :: Exp -> Eval a+exit e = Eval (\_ _ -> return e)+callCC :: (((Maybe Char, Int) -> a -> IO Exp) -> Eval a) -> Eval a+callCC f = Eval $ \dat cont -> let Eval cp2 = f cont in cp2 dat cont+step :: Eval ()+step = Eval (\(c,i) cont -> if i<1 then return E else cont (c,i-1) ())++------------------------------------------------------------------------+-- Interpretation in the Eval monad++eval :: Exp -> Eval Exp+eval (App e1 e2) = do+ f <- eval e1+ case f of+ D -> return (D1 e2)+ _ -> eval e2 >>= apply f+eval e = return e++apply :: Exp -> Exp -> Eval Exp+apply K x = return (K1 x)+apply (K1 x) _ = return x+apply S x = return (S1 x)+apply (S1 x) y = return (S2 x y)+apply (S2 x y) z = eval (App (App x z) (App y z))+apply I x = return x+apply V _ = return V+apply C x = callCC (\c -> apply x (Cont c))+apply (Cont c) x = throw c x+apply D x = return x+apply (D1 e) x = do f <- eval e; apply f x+apply (Dot c) x = step >> io (putChar c) >> return x+apply E x = exit x+apply At f = do+ dat <- io $ catch (getChar >>= return . Just) (const $ return Nothing)+ setCurrentChar dat+ apply f (case dat of Nothing -> V ; Just _ -> I)+apply (Ques c) f = do+ cur <- currentChar+ apply f (if cur == Just c then I else V)+apply Pipe f = do+ cur <- currentChar+ apply f (case cur of Nothing -> V ; Just c -> (Dot c))+apply (App _ _) _ = error "Unknown application"
+ Main.hs view
@@ -0,0 +1,39 @@+{-# LANGUAGE PatternGuards #-}++module Main where++-- A time- and output-limited unlambda++import System.Posix.Resource+import Data.Char+import System.IO++import Language.Unlambda++main :: IO Exp+main = (setResourceLimit ResourceCPUTime $ ResourceLimits (ResourceLimit 5) (ResourceLimit 5)) >> run++run :: IO Exp+run = do+ expr <- parse stdin+ let (Eval cp) = eval expr+ cp (Nothing, 2048) (const return)++------------------------------------------------------------------------+-- Parsing of the Unlambda program directly from handle+--+parse :: Handle -> IO Exp+parse h = do+ c <- catch (hGetChar h) (\_ -> error "Parse error at end of file")+ case toLower c of+ d | d `elem` " \t\n" -> parse h+ '`' -> do e1 <- parse h+ e2 <- parse h+ return (App e1 e2)+ '#' -> hGetLine h >> parse h+ '.' -> hGetChar h >>= return . Dot+ '?' -> hGetChar h >>= return . Ques+ _ | Just fn <- lookup c table -> return fn+ | otherwise -> error $ "Unknown operator " ++ show c++ where table = zip "ksivcdre@|" [K,S,I,V,C,D,Dot '\n',E,At,Pipe]
+ Setup.hs view
@@ -0,0 +1,5 @@+#!/usr/bin/runhaskell++import Distribution.Simple++main = defaultMainWithHooks simpleUserHooks
+ unlambda.cabal view
@@ -0,0 +1,30 @@+name: unlambda+version: 0.1++license: GPL+license-file: LICENSE+author: Ørjan Johansen <oerjan@nvg.ntnu.no>+ Don Stewart <http://www.cse.unsw.edu.au/~dons>+-- maintainer: Cale++stability: Stable+category: Compilers/Interpreters+synopsis: Unlambda interpreter+description: This is an interpreter of the Unlambda language,+ written in the pure, lazy, functional language Haskell.++build-type: Simple+Cabal-Version: >= 1.2+tested-with: GHC==6.8.2++executable unlambda+ main-is: Main.hs+ build-depends: base>3, unix++library+ exposed-modules: Language.Unlambda++ build-depends: base, array, mtl++ ghc-options: -Wall+ ghc-prof-options: -prof -auto-all